The present invention relates to a cam follower having a roller which is in rolling contact with a cam of an engine, and more particularly to the prevention of occurrence of peeling in the roller and pitching in the mating cam.
In a related cam follower, innumerable minute concave depressions are formed randomly on an outer surface of a roller so as to enhance an oil film forming coefficient on an outside-diameter rolling surface thereof to thereby secure a sufficient oil film thickness, whereby a contact portion of the roller is prevented from being brought into contact with metal, so as to prevent the occurrence of peeling damage to and wear of the outside-diameter rolling surface of the roller regardless of the surface roughness of the surface of the mating cam, thereby making it possible for the roller to obtain a long service life (refer to, for example, Japanese Patent Publication No. 2594339).
In the related cam follower, although the occurrence of peeling in the outside-diameter rolling surface of the roller can be prevented by forming randomly innumerable minute concave depressions on the outer surface of the roller, in the event that the hardness of the cam is low, since the contact surface pressure between roughness projections of the roller is high due to the contact area being small, there has been caused a problem that pitching is produced in the mating cam.